Jaguar's biggest, baddest cat unleashed

The Jaguar XJR, unveiled at the New York Auto Show this week, will be the company's fastest four-door when it goes on sale later this year.

With 405kW of supercharged performance, sports suspension and a subtle sports bodykit, Jaguar expects the XJR to do 0-100km/h in 4.6 seconds, two-tenths quicker than the current Jaguar speed king, the XFR, and just a tenth shy of its nearest rival, the Mercedes-Benz S63 AMG.

The new XJR will be the fourth model from Jaguar's R performance brand after the XKR coupe and convertible, and the XFR mid-size sedan.

It's based on the XJ limousine, Jaguar's rival to the BMW 7 Series and Mercedes-Benz S-class, and will wear a price tag just shy of $400,000 when it hits Australia around November 2013, a premium of almost $40,000 over the XJ Supersport on which it is based.

The extra money cranks the 375kW/625Nm supercharged V8 up to 405kW and 680Nm, and brings a more responsive sport mode for the eight-speed transmission.

The XJR's suspension has been overhauled with new springs and active dampers, and a bespoke active electronic differential said to provide better traction under acceleration.

The steering system has also been finessed to provide better weighting and feedback, and a 'Track' setting added to the electronic stability control. Specially developed 20inch Pirelli tyres are 20mm wider front and rear.

The new F-Type's high performance braking option completes the XJR's mechanical modifications.

According to Mike Cross, Jaguar's drift king and chief engineer, "the XJR offers greater steering precision, higher levels of control and enhanced high speed stability, with little trade-off in refinement".

Visual changes are designed to subtly communicate the XJR's enhanced abilities without overpowering the car's luxury positioning.

A deep front spoiler with twin air intakes, sports skirt on the side that reduces drag, and vestigial rear spoiler are the most obvious telltales, along with unique 20inch black alloy wheels.

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